I expect the cracking of the manifold is due to thermal stress rather than corrosion. The ceramic coatings do the best job of keep the heat in the exhaust gas rather than letting it move into the manifold. That should reduce the stress.

This is a 2 stroke engine right? Generally the 2 stroke exhaust is significantly cooler than 4 stroke. The manifold shouldn't be getting that hot - unless its running really lean. Is there any sticky goo in the rest of the exhaust pipe?

No idea on sticky goo. So I cleaned up the pipe and hit it with bbq paint, dropping it off tonight. This is a 15yo snowmobile if the first Y pipe lasted 10 I bet this one goes another 10 easy, heck feels like this winter is almost over already.

I didn't catch it the first time I read it, but you did say "crack". That tells me paint wasn't the reason for common failures, it's expansion. So, others comments about a gusset and a ceramic coat make sense to me. Still, I probably wouldn't do that THIS season but would wait till summer given what you said. If you want a professional opinion ( worth far more than mine) I have a crew of seasoned professional welders on site in boulder for the next 3-4 months. These guys weld exotic pipes for a living, so we could ask them for $.02.

Yeah that's what I was getting at. It's the expansion and contraction of the metal with the flanges clamped down hard that's probably causing it to crack. Making it stiffer with gussets and stuff can backfire and that's why I was mentioning stuff I've done in the past just moving the crack somewhere else. The mention of a slip plate seems interesting.

That or you could build a new one with one half slipping into the other with a sleeved joint or something? that might not be too hard.

also, think 2uzfe log style manifold cracking. going to headers helps maybe because there is more flex int eh assembly with longer pipes. in this scenario you can't extend the y pipe halves because it'd mess with tuning.